植物滞留系统中草本植物对磷的去除效果研究

以黑麦草、地毯草、高羊茅和早熟禾为研究对象,研究4种草本植物在植物滞留系统中不同介质、不同入口浓度下对城市非点源(人工降雨径流)中污染物磷的富集能力和去除效果。结果表明:4种草本植物对人工降雨径流中的磷均有明显的去除效果,TP平均去除率在60.24%～83.56%。不同草本植物去除人工降雨径流中TP的能力,从强到弱的顺序依次为:早熟禾>黑麦草>地毯草>高羊茅。其中,对于同一种草本植物同样的入口浓度情况下,沙土Ⅱ为最佳土壤介质,具有最佳的去除磷能力。4种草本植物对磷的去除率随入口浓度的增加,去除率也随之增加。4种草本植物地上部和地下部磷累积量分别为2.27～5.92 mg和4.33～6.46 mg;其中黑麦草磷累积总量最高,其次是地毯草,最低的是早熟禾。综合考虑污染物去除率和磷在植物体内的累积量,交替种植早熟禾和黑麦草可提高植物滞留系统去磷能力且有利于延长系统寿命。

STUDY ON REMOVAL EFFICIENCY OF PHOSPHORUS BY GRASSES IN BIORETENTION

Based on the laboratory study,removal efficiency of total phosphorus(TP) by Lolium perenne,Axonopus compressus,Festuca arundinacea,and Poa annua in different soil media and in different inflow concentration of urban non-point source pollution was researched.The results showed that the sandⅡ was the best media for bioretention.And with the increasing of inflow concentration,the phosphorus removal rate was improved by the four herbaceous plants.The results also indicated that the content of TP was 2.27~5.92 mg and 4.33~6.46 mg in shoots and in roots of four herbaceous plants,respectively.The highest accumulated content of TP was in Lolium perenne,and then Axonopus compressus,the lowest in Poa annua.The average removal rate to TP was 60.24%~83.56%,respectively.According to TP removal capacity of four herbaceous plants,the order was: Poa annua>Lolium perenne>Axonopus compressus>Festuca arundinacea.The comprehensive evaluation results showed that alternately plants the Poa annua and Lolium perenne in the bioretetnion,which was helpful to improve phosphorus removal efficiency and prolong the working life of bioretention.